Update README.md

Added details of requirements for compiling
#8 Scrolling of the map area works, but scroll bars are still needed.
#9 Drawing area is fixed size now, but still need the ability to set
size

Scaling causes issue with it, this need to be fixed
Update README.md

Added details of requirements for compiling
Merge branch 'master' of git@github.com:LupusUmbrae/map.git
Code merged back to master. All headers documented and redundant method
declarations removed.
#12 Json usage extracted to seperate class

MapTexture now has common code to convert from surface to texture, this
also adds the texture to the loadedTextures vector
Documentation updated
Additional doxygen docs added
#13 a somewhat unsafe and pretty poor input dialog box now works